Light‐Induced Ce–Ov–Ni Motifs Enable Hydrogen‐Poisoning‐Resistant Photothermal NH 3 Decomposition

ABSTRACT NH 3 is an attractive hydrogen carrier, but efficient H 2 release is hindered by N–H bond cleavage and hydrogen poisoning. Herein, we develop Ni nanoparticle‐supported CeO 2 (Ni/CeO 2 ) for low‐temperature photothermal NH 3 decomposition. Light irradiation is accompanied by the dynamic generation of oxygen vacancies on CeO 2 , which couple with adjacent Ni sites to form Ce–Ov–Ni motifs, indicating that illumination can regulate the catalyst surface state beyond its thermal contribution. Experiments and DFT calculations indicate that these interfaces create differentiated local environments for NH 3 activation and product evolution. Oxygen‐vacancy‐associated sites favor NH 3 adsorption, N–H bond activation, and N‐containing intermediates, whereas adjacent Ni sites accommodate H migration and recombination. Moreover, vacancy‐induced electronic modulation weakens H 2 adsorption on Ni, thereby facilitating H 2 release. Such site differentiation and facilitated hydrogen removal reduce the competitive occupation of active sites by N‐ and H‐containing species and contribute to the resistance to hydrogen poisoning. Under photothermal conditions, 10 wt.% Ni/CeO 2 achieves 96.3% NH 3 conversion at 450°C, versus 42.5% under thermal catalysis, and maintains >95% conversion at a GHSV of 18,000 mL·gcat −1 ·h −1 . It delivers 20.09 mmol·gcat −1 ·min −1 H 2 with 50 h stability. This work demonstrates light‐induced oxygen‐vacancy–metal interfaces for efficient, hydrogen‐poisoning‐resistant NH 3 ‐to‐H 2 conversion.